ИСТИНА

In this work a library of low band gap star-shaped oligomers with alkyldicyanovinyl acceptor linked through (oligo)thiophene conjugated spacers to triphenylamine or tris(2-methoxyphenyl)amine donor group was created. Due to intramolecular charge transfer and aggregation in the solid state they absorb the solar light in a wide spectral range, from 350 to 600-700 nm. Alkyldicyanovinyl groups differ from regular dicyanovinyl groups by better solubility and higher stability due to the absence of acidic proton. Systematic variations of the alkyl chain length and the number of conjugated thiophene rings in the molecules allowed to elucidate the relationship between their molecular structure and different physical properties, including their solubility, absorption spectra, phase behavior, morphology and structure in thin films, as well as semiconducting and photovoltaic properties. Bulk heterojunction organic solar cells (BHJ OSC) prepared from these molecules as donors and PCBM[70] as acceptor by solution processing showed power conversion efficiency up to 5.4%. The peculiarities of these molecules in BHJ OSC are high open circuit voltage Voc, up to 0.96 – 1.08 V, and relatively high fill factor FF, up to 54%. These molecules can form columnar mesophases, which bring an additional factor for improving their efficiencies by possible ordering the bulk heterojunction